Fiber-drafting element used in textile spinning



3, 1954 M. BALKIN ET AL 2,685,109 FIBER-DRAFTING ELEMENT USED IN TEXTILESPINNING Filed May 2, 1950 2 Sheets-Sheet l bAi-KINAN DENYS TURNERAdm/cs0 Gr/Y Br 3 ATTORNEY g- 1954 M. BALKIN ET AL DRAF'TING ELEMENTUSED IN TEXTILE SPINNING FIBER- 2 Sheets-Sheet 2 Filed May 2, 1950 MARKBALKIN AND DE (4Y5 BTURNER B)? \YMM ATTORNEY Patented Aug. 3, 1954 :lFICE Mark Balkin and Denys Grahame Turner, Newcastle-upon-Tyne, England,assignors to George ed, Newcastle-upon- Application May 2, 1950, SerialNo. 159.606

4 Claims.

This invention relates to fibre-drafting elements used in textilespinning, namely the coverings of rollers used in spinning textilefibres, and known as roller cots and spinning cots, and for largediameter rollers as tyres, and draft aprons used in spinning textilefibres.

Roller coverings used in spinning textile fibres are mounted oncylindrical metal rollers or spindles and each runs in contact with afluted metal roller. Textile fibres are engaged between the two rollers,and are drawn by passing therefrom into engagement by a similar pair ofrollers rotating at a higher peripheral speed.

A draft apron is an endless belt or tape, between an opposed pair ofwhich, led around opposed nipped and supported in their a pair ofdrafting rollers rotatsurface speed than that of the passage towards ingat a greater drafting aprons.

To improve resistance to abrasion, fibre-draftboth fibre-drafting rollercoverings made of natural rubber have been tried, but these fail asnatural rubber has poor resistance to oils, and fibre-drafting rollercoverings and draft aprons made thereof swell and distort in service.

With the development of oil-resistant synthetic rubbers, such ascopolymers of butadiene and acrylic nitrile, it has been proposed tomake fibre-drifting elements of oil-resistant synthetic rubber, as suchwould be expected to show good resistance to abrasion. HOV-lever,although initially a satisfactory fibre-drafting surface can be madefrom oil-resistant synthetic rubber, it has been found in practice thatit often rapidly deteriorates in efiiciency, resulting in dirty running,namely the tendency for fibres to cling to and go around with thefibre-drafting element. Such carried-around fibres, which are draggedout of the line of fibres, cause the production of uneven yarn havingthin places where they have been removed. Moreover, these fibres collectas waste on the clearers, entailing an undesirable loss of material.Also, occasionally, such fibres may re-attach themselves elsewhere alongthe line of fibres being drafted, causing the production of a thickeruneven place in the yarn.

It has sometimes been found that if oil-resistant synthetic rubberfibre-drafting elements which run dirty are cleaned or lightly buffed,they function satisfactorily again.

We have found after close study that in many cases the cause of dirtyrunning of oil-resistant synthetic rubber fibre-drafting elements, isthe presence of oily,

greasy or waxy material on the surface of the fibre-drafting element.This contamination is mainly derived from the fibres which are beingdrafted.

Most textile fibres such as the natural fibres of cotton and wool areassociated with fatty or waxy materials. For instance, cotton maycontain up to 1% of natural wax of complex chemical composition.Incidentally, this wax serves a useful purpose in cotton spinning, as itis a desirable lubricant or softener of the fibres, and therefore it isnot desirable to remove it before spinning.

Natural wool fibre normally contains an excessive amount of greasy orfatty matter, such as wool fat, and suint or wool sweat. Most of theseimpurities are removed from the wool by washing or other treatmentbefore spinning the wool,

wise the fibres would be harsh and brittle. It is in fact usual to applyfurther controlled quantities of special oils to the wool fibres tolubricate them prior to spinning.

We have observed that in the course of drafting, whereas thefibre-drafting element was originally clean and free from grease, itgradually develops a greasy or oily surface, due to contamination by oilor grease derived from the fibres passing over and in contact with thesynthetic rubber fibre-drafting surface. Such film or grease or oilprovides a tacky surface on the synthetic rubber which causes theadherence thereto of fibres from the line of fibres being drafted,leading to the dirty running and the disadvantages associated therewithdescribed above. The dirty running gradually becomes worse as the greasyoxidises or congeals and thereby becomes more tacky in character.

Contamination by oil or grease of the fibredrafting surface of afibre-drafting element is particularly objectionable, when thefibre-drafting element, either a roller covering or a draft apron, has afibre-drafting surface provided by finely cellular oil-resistantsynthetic rubber.

The exposed cells at the surface of the finely cellular synthetic rubberfibre-drafting element initially provide a finely rough surface suitablefor fibre-drafting. However, the finely rough surface exposed bygrinding the surface of the cellular rubber, is particularly susceptibleto confilled with the oil, grease or wax, which nullifies the advantagesof the rough surface. In this manner the surface not only tends tobecome oily or greasy, but also smooth. Thus with cellular rubber, thesurface advantage of roughness becomes lost, although the cushioningeffect of cellular rubber with unruptured cells and capability ofvolumetric compression thereof, are retained.

We have made many experiments endeavouring to find a means of preventingthe accumulation of oil or grease on an oil-resistant synthetic rubberfibre-drafting element. It was found that the normal oil-resistantsynthetic rubbers, whereas they are oil-resistant in the sense that theydo not absorb oil and thereby become softened and swollen, on the otherhand, are not oilrepellant, and, therefore, are readily wetted orcontaminated by oil or grease adhering to their surface.

The object of the present invention is to render the fibre-draftingsurface of an oil-resistant synthetic rubber fibre-drafting element,also oilrepellant. The rubber may be plain, i. e. solid, or finelycellular. We have discovered that by the addition to oil-resistantsynthetic rubbers of so-called water-soluble gums of vegetable originwhich are colloidal in nature, fibre-drafting elements can be madetherefrom which do not tend to develop greasy or sticky surfaces evenafter continuous running in contact with fibres which normally containoil or grease. In consequence dirty running is practically eliminatedand good uniform yarn can be spun. In addition, waste is therebyreduced, and the necessity of frequent cleaning or buffing of thefibre-drafting surfaces is eliminated.

By water-soluble gums of vegetable origin are meant vegetable substanceswhich have the following general characteristics, namely: They aresoluble or can be dispersed in water to give thick colloidal solutions.They are hydrophilic. They are generally of complex indefinitecomposition consisting mainly of carbon, hydrogen and oxygen and arechemically carbohydrates or closely related to carbohydrates. Examplesof such water-soluble gums are gum tragacanth, gum arabic, starch anddextrin.

Suitable water-soluble vegetable gums for adding to oil-resistantsynthetic rubber to render it oil-repellant, are those mentioned, namelygum tragacanth, gum arabic, starch and dextrin. Suitable proportions are50 parts by weight of the gum to 100 parts by weight of rubber.

Accordingly, according to the present invention the fibre-draftingsurface of a fibre-drafting element is provided by an oil-resistantsynthetic rubber composition, either plain or finely cellular,containing a substantial proportion of a colloidal water-solublevegetable gum.

By substantial is meant sufilcient to provide an effective oil-repellantaction. The effectiveness of the oil-repellant action will depend uponthe nature and greasiness of the fibre which is drafted, and for somekinds of fibres a proportion of parts by weight of colloidalwater-soluble vegetable gum to 100 parts by weight of oilresistantsynthetic rubber could be sufiicient. The amount of the gum present inthe rubber composition should not exceed that which would render thecomposition unduly hard and for this reason usually does not exceed 80parts by weight of colloidal water-soluble vegetable gum to 100 part byweight of oil-resistant synthetic rubber.

The gum is first made into a thick paste with water and the paste isadded to the synthetic rubber on the mixing mill in the normal course ofmixing the synthetic rubber composition. The other usual ingredientssuch as zinc oxide, sulphur, vulcanising accelerators, and fillers suchas carbon black or whiting, together with, for finely cellular rubber, agassing agent, such as sodium bicarbonate, are added. The water in thepaste gradually evaporates off.

It has been found that water-soluble vegetable gums blend very well withoil-resistant synthetic rubbers, such as butadiene-acrylic nitrile.

ter the mixing, the composition is processed in the usual way, forexample by being extruded, and is vulcanised in steam or in a hydraulicpress, to make a draft roller cot or a draft apron.

The gum exercises a stiffening effect on the final vulcanised product.More or less than 50 parts by weight of gum to parts by weight ofsynthetic rubber can be used depending on the type of vulcanised productrequired.

When the synthetic rubber drafting element is finely cellular, the cellsthereof are unbroken gasfilled cells. The cellular structure is exposedat the fibre-drafting surface, by trimming-off the smooth surface lefton vulcanisation. Usually and conveniently, the surface is trimmed-01fby grinding, but other methods, including even wear during initial use,are not excluded.

Representative examples of fibre-drafting elements to which theinvention is applied are shown in the accompanying drawings, in which-Fig. 1 is a perspective view of an unmounted roller cot of plaingun-containing oil-resistant synthetic rubber, and

Fig. 2 is a similar perspective view of an unmounted finely cellulargum-containing oil-resistant synthetic rubber roller cot, after theouter periphery has been ground to expose the cellular structure and theends have been trimmed.

Fig. 3 is a perspective view of a double boss roller with two mountedfinely cellular gum-containing oil-resistant synthetic rubber rollercots, one of which is cut away to expose longitudinal sections of thecot.

Fig. 4 is an isometric view of an unmounted oil-resistant syntheticrubber draft apron with an intermediate textile fabric reinforcement anda plain gum-containing oil-resistant synthetic rubber fibre-draftingsurface layer.

Fig. 5 is an isometric view similar to Fig. 4 and showing a similarunmounted draft apron but with a finely cellular fibre-drafting surfacelayer.

Fig. 6 is a perspective view showing in the operative position a pair ofplain surfaced draft aprons like that shown in Fig. 4, but on a smallerscale.

An unmounted roller covering or roller cot a composed of plaingum-containing oil-resistant synthetic rubber is shown in Fig. l. Asimilar but finely cellular roller covering or roller cot b is shown inFig. 2. These roller coverings are mounted on metal spindles, a pair offinely cellular roller coverings I) being shown in Fig. 3, each mountedon a separate boss 0 of a metal spindle d.

An unmounted draft apron c composed of plain gum-containingoil-resistant synthetic rubber with an intermedate textile fabricreinforcement ,"f. is shown in Fig. 4. A similar draft apron, but with afinely cellular gum-containing oil-resistant synthetic rubberfibre-drafting surface layer 9, is shown in Fig. 5. In use a pair ofdraft aprons e are, as shown in Fig. 6, each led around a separateroller h of a pair of opposed rollers and are extended to run in mutualcontact along a portion of their travel, by each passing loosely aroundthe respective arm 2' of the device, called a tensor, which holdstogether the fibre-conveying portions of the two draft aprons e.

composition a colloidal water-soluble vegetable gum in the proportion ofat least 10 parts by Weight of said gum to 100 parts by weight of saidrubber.

2. A fibre-drafting element according to claim 1 in which saidfibre-drafting surface layer is finely celluular.

water-soluble vegetable gum in the proportion of at least 50 and under80 parts by weight of said gum to 100 parts by Weight of said rubber.

4. A fibre-drafting element according to claim 3 in which saidfibre-drafting surface layer is finely cellular.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,175,798 Hauser Oct. 10, 1939 2,304,656 Rockofi Dec. 8, 19422,343,559 Kirby et a1 Mar. 7, 1944 2,381,706 Wilson Aug. 7, 19452,385,319 Eustis et a1. Sept. 18, 1945 2,457,542 Golden Dec. 28, 19482,507,869 Rothermel May 16, 1950

1. A FIBRE-DRAFTING ELEMENT HAVING A FIBREDRAFTING SURFACE LAYERCONSISTING OF AN OIL-RESISTANT SYNTHETIC RUBBER COMPOSITION HAVINGPERMANENTLY BLENDED WITH THE RUBBER PHASE OF SAID COMPOSITION ACOLLOIDAL WATER-SOLUBLE VEGETABLE GUM IN THE PROPORTION OF AT LEAST 10PARTS BY WEIGHT OF SAID GUM TO 100 PARTS BY WEIGHT OF SAID RUBBER.